The two-wheel motorcycle is a type of common vehicle, which has the advantages of small dimensions, low price, low-cost, easy-use compared with the ones of an automobile. At the same time, however, this type of vehicle has disadvantages as far as safety and comfort are concerned. In order to overcome these shortcomings, many people have made great efforts on it. In short, there are three general ways to solve these problems:
The first way is to equip the motorcycle with a windscreen in the front of the vehicle and a cage construction over or behind the motorcycle, as in BMW type C1, but the shortcomings are that there is no protection on the two sides of the motorcycle, therefore this does not completely solve the safety and comfort problem previously mentioned.
The second way is to equip the motorcycle with a closed surrounding shell, as in Chinese patent application N96248476.8, which discloses a kind of “closed two-wheel motorcycle.” Its structure is like the one of a car, which includes a closed structure around the motorcycle, with doors on both sides and in which each door is divided into two parts: a top part and a bottom part, which are connected by a hinge, so that the bottom part opens on the outside, in order to let the driver's feet touch the ground when the motorcycle is to slow down or to stop. But it has some problems:    1. The top and bottom parts are connected by a hinge and the bottom part is made of flexible material so to allow the driver's leg to stretch out to touch the ground; therefore, this structure is not completely closed.    2. It is not easy to open the door and it results rather complicated.    3. At the time to slow down or to stop the motorcycle, the driver needs to stretch out the feet to balance the motorcycle while the motor is moving: if the driver is not careful, it's very easy for the driver's feet to be caught outside the door, therefore this is a very serious safety concern.
The third way is to add a shell around the two-wheel motorcycle, such as in the Chinese patent application N.98106572.4, which also discloses a kind of closed two-wheel motorcycle. This solution equips the motor-cycle with auxiliary wheels and a controlling set, which can control a state of opening and closing so that it can command the auxiliary wheel to touch the ground to balance the motorcycle instead of the person's feet when the motor is to start or stop. But there are problems:    1. The structure is complicated and it is not easy to be controlled. Furthermore, once the controlling set does not work, it is very difficult to stop the motorcycle.    2 The amount of power needed to balance the motorcycle is directly related to the condition of the ground and the speed of the motorcycle; therefore, the auxiliary wheels extend to the ground by means of a complex controlling set. This cannot provide the proper power to support the motorcycle and also cannot follow the dynamics of the ground conditions and the speed of the motorcycle, like the previously mentioned example where the driver can control the vehicle with his feet. However the method provided by this vehicle is very difficult to adapt to and the driver might have control and handling problems.    3. Changing from one manner of driving to another requires very different approaches, so there are difficulties for a driver to follows the changes. When driving such a motorcycle, people must raise the auxiliary wheel. The motor has two connecting points with the ground, and it is the same as driving an old motor, so the driver must change the center of gravity of his own body and the engine to achieve balance. We call this situation as “two-wheel state of driving.” When the motorcycle has four touching points with the ground, as the auxiliary wheel touching the ground, the driver need not consider the effect of balance with respect to the center of gravity of the motorcycle and the driver's body, and the motor can not be overturned because of un-balancing. We call this other situation as “multi-wheel state of driving.” Under such other condition, the driver needs not to change the center of gravity of his own body and the engine to keep the vehicle in balance. Thus, the driver needs to change repeatedly from the former “state” to the later “state.” The manner of driving changes drastically and it's hard for the driver to adapt to these changes, and also it has serious controlling difficulties and might require additional skills. So this solution adds dangerous factors in driving the motorcycle.